1. The Field of the Invention
This invention relates generally to separation of materials. More specifically, foreign materials (contaminants) are removed from food products, where the food products can be processed by screening through a mesh or membrane-like material used in combination with a centrifuge system.
2. The State of the Art
It is desirable to eat food products which are free of contaminants. This is particularly true in this day of increasing awareness of the hazards which contaminated food products pose to consumers. Accordingly, food processing companies are under increasing pressure to provide food to the consumer that is always safe for consumption. This pressure on the food processor remains high despite significant government regulations already in place which require minimum health standards. Nevertheless, public awareness and concern has created a need for continued development of contaminant detection and elimination technologies. It should also be realized that even when contaminants do not pose a health hazard to the consumer, awareness of their existence in food products can adversely affect the fortunes of a company if a food quality problem is even perceived by the consumer.
A significant portion of food contaminants can be removed during processing. The processing referred to can be any stage of food preparation (where the term "food" is hereinafter used to refer to the terms food and food products) such as the bringing together of raw materials to be combined to make a processed food product.
Food contaminant removal can be as simple as the washing of food before it is either packaged in a raw form or used as an ingredient of another processed food. However, washing is obviously a wet cleaning process which can not be used on all foods.
The food contaminant removal processes of greatest relevance to the present invention pertain to those which are accomplished in food processing lines. For example, the prior art teaches X-ray detection systems for locating solid contaminants. However, these systems are costly and prone to error because of their reliance on human intervention and concentration.
A different type of system is magnetic detection, where magnetic contaminants can be thereby removed. A screen or mesh has also been employed in contaminant separation. However, screens have been primarily used in cleaning liquids. The effectiveness of screens with solids is compromised by the substantial force often required to keep the solids flowing through the screen. Still another system relies on an electrostatic property of the contaminant. For example, by bringing a charged surface near to the contaminant, those contaminants which are attracted to the charged surface can be separated from the food.
Consequently, it would be an improvement over the state of the art to provide a more reliable and automatic method and apparatus for removing solid contaminants from both solid and liquid food. It would be a further improvement if the solid contaminants could be removed regardless of their magnetic or electrostatic properties.